1. Field of the Invention
The present invention relates to a feeding apparatus for a waveguide and related communication apparatus, and more particularly, to a feeding apparatus for a waveguide and related communication apparatus capable of reducing layout area of a printed circuit board.
2. Description of the Prior Art
With rapidly growing wireless communication technology, a wireless communication device should be of small size and light weight. In a wireless front-end module, a waveguide is often used as a transition line in microwave and millimeter circuitry due to its low-loss transmission.
Please refer to FIG. 1. FIG. 1 is a schematic diagram of transition from a microstrip line to a waveguide in the prior art. Axes X, Y and Z indicate three orthogonal coordinate axes. As shown in FIG. 1, a waveguide 102 is semicircle shaped. In general, a microstrip line printed circuit board 104 extends to the waveguide 102 perpendicular to a diametric side of the waveguide 102 by using a microstrip line probe 106 in order to feed a signal. Please refer to FIG. 2. FIG. 2 is a top-view diagram of a layout of the microstrip line printed circuit board 104 in the prior art. In the prior art, transition from the microstrip line to the waveguide is designed symmetrically, and the microstrip line probe 106 extends to the semicircle region in a perpendicular direction. Therefore, the microstrip line printed circuit board 104 has a large transverse area, i.e. in a first direction 100. However, as shown in FIG. 2, a microwave circuit 202 coupled to the microstrip line probe 106 does not need such a large layout area in practice. But, due to the feeding approach, the microstrip line printed circuit board 104 must have the large transverse area, which generates a large, unused blank region 204. In other words, distribution of the layout of the microwave circuit 202 is sparse, wasting printed circuit board area and increasing manufacturing cost.